Edge runtime cost realities: Vercel Edge vs serverless
Edge runtime wins on latency and cold-start, loses on cold cache and invocation cost at high traffic. The crossover point sneaks up on you.
Edge runtime is genuinely faster — global TTFB, no cold starts, geographic affinity. The marketing isn't wrong. The pricing is also not wrong; it just isn't what most teams think.
At low traffic, Edge is cheaper than Lambda or Vercel serverless. The crossover happens around mid-six-figure invocations per month, where Edge's per-request pricing starts beating cold-start-discounted serverless. After that, Edge is more expensive — sometimes 2-3x.
The sane default I land on: Edge for the route shell (auth, rewrites, A/B variants) and serverless for the data-heavy work. That keeps TTFB low for the LCP-critical path while keeping invocation cost under control on the long tail. Pure-Edge architectures look great on slides and surprise you on the bill.